Implements
https://github.com/llvm/wg-hlsl/blob/main/proposals/0026-symbol-visibility.md.
The change is to stop using the `hlsl.export` attribute. Instead,
symbols with "program linkage" in HLSL will have export linkage with
default visibility, and symbols with "external linkage" in HLSL will
have export linkage with hidden visibility.
Reverts llvm/llvm-project#123853
The introduction of `reflect-error.ll` surfaced a bug with the use of
`report_fatal_error` in `SPIRVInstructionSelector` that was propagated
into the pr. This has caused a build-bot breakage, and the work to solve
the underlying issue is tracked here:
https://github.com/llvm/llvm-project/issues/124045. We can re-apply this
commit when the underlying issue is resolved.
This PR relands
[#122992](https://github.com/llvm/llvm-project/pull/122992).
Some machines were failing to run the `reflect-error.ll` test due to the
RUN lines
```llvm
; RUN: not %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o /dev/null 2>&1 -filetype=obj %}
; RUN: not %if spirv-tools %{ llc -O0 -mtriple=spirv32-unknown-unknown %s -o /dev/null 2>&1 -filetype=obj %}
```
which failed when `spirv-tools` was not present on the machine due to
running the command `not` without any arguments.
These RUN lines have been removed since they don't actually test
anything new compared to the other two RUN lines due to the expected
error during instruction selection.
```llvm
; RUN: not llc -verify-machineinstrs -O0 -mtriple=spirv64-unknown-unknown %s -o /dev/null 2>&1 | FileCheck %s
; RUN: not llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown %s -o /dev/null 2>&1 | FileCheck %s
```
Fixes#99152
Tasks completed:
- Implement `reflect` in `clang/lib/Headers/hlsl/hlsl_intrinsics.h`
- Implement the `reflect` SPIR-V target built-in in
`clang/include/clang/Basic/BuiltinsSPIRV.td`
- Add a SPIR-V fast path in `clang/lib/Headers/hlsl/hlsl_detail.h` in
the form
```c++
#if (__has_builtin(__builtin_spirv_reflect))
return __builtin_spirv_reflect(...);
#else
return ...; // regular behavior
#endif
```
- Add codegen for the SPIR-V `reflect` built-in to
`EmitSPIRVBuiltinExpr` in `clang/lib/CodeGen/CGBuiltin.cpp`
- Add HLSL codegen tests to
`clang/test/CodeGenHLSL/builtins/reflect.hlsl`
- Add SPIR-V built-in codegen tests to
`clang/test/CodeGenSPIRV/Builtins/reflect.c`
- Add sema tests to `clang/test/SemaHLSL/BuiltIns/reflect-errors.hlsl`
- Add SPIR-V sema tests to
`clang/test/CodeGenSPIRV/Builtins/reflect-errors.c`
- Create the `int_spv_reflect` intrinsic in
`llvm/include/llvm/IR/IntrinsicsSPIRV.td`
- In `llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp` create the
`reflect` lowering and map it to `int_spv_reflect` in
`SPIRVInstructionSelector::selectIntrinsic`
- Create a SPIR-V backend test case in
`llvm/test/CodeGen/SPIRV/hlsl-intrinsics/reflect.ll`
Additional tasks completed:
- Implement sema check for the `reflect` SPIR-V built-in in
`clang/lib/Sema/SemaSPIRV.cpp`
- Required for HLSL codegen to work via the SPIR-V fast path, because
the types defined in `clang/include/clang/Basic/BuiltinsSPIRV.td` are
being overridden
- Create SPIR-V backend error test case in
`llvm/test/CodeGen/SPIRV/opencl/reflect-error.ll`
- Since `reflect` is only available in the GLSL extended instruction
set, using it in OpenCL should result in an error
Incomplete tasks:
- Create SPIR-V backend test case in
`llvm/test/CodeGen/SPIRV/opencl/reflect.ll`
- An OpenCL test is not applicable in this case because the [OpenCL
SPIR-V extended instruction
set](https://registry.khronos.org/SPIR-V/specs/unified1/OpenCL.ExtendedInstructionSet.100.html)
does not include a `reflect` function
